In an attempt to encourage Asian companies to invest in Philadelphia, Oh went on a weeklong trade mission to Korea in September. He introduced the Korean company that wants to install platform screen doors on Philadelphia subway stops, TIS Inc., to SEPTA last year after that trade mission.

Platform screen doors were first installed on a subway station in St. Petersburg, Russia, in 1961. The doors offer several advantages to the types of open platforms seen in most transit systems in the United States. They only open when a train approaches and lines up with the platform doors, which helps prevent accidental falls and suicides. They also keep tracks cleaner, help with climate control in underground stations and reduce the amount of wind felt by passengers as trains whiz by.

Other U.S. cities have explored installing platform screen doors. New York City’s MTA has considered the plan several times over the past few years alone, but keeps rejecting it due to logistical issues and cost (about $1 million a station in a system with 468 stops). In the U.S., these types of glass doors are usually seen in specialized, automated systems like airport trams.

Platform screen doors are considered very safe, but there have been incidents. Late last year in Beijing, a woman was dragged to death after she was caught between the screen doors and the doors of the train. A subway worker told the website caixin.com that sensors that detect if people are caught between the two sets of doors could have prevented the death.

TIS, an information technology company, would pay to construct and install the platform doors. The company says it would make money from ads on the glass doors. Underground stops would get full-size platform screen doors, while outdoor stops would get half-size barriers. Discussions have been underway, as Oh first introduced TIS to SEPTA in October. Representatives from SEPTA and TIS met on October 30th. “You can do it in our city, and then you could headquarter your [U.S.] operation in Philadelphia as you start to marketing to other parts of the U.S.,” Oh told Metro in an October article on platform screen doors.

It seems unlikely SEPTA will have platform screen doors anytime soon. Several transit agencies have studied the possibility of screen doors, but found retrofitting the stations would be too costly. SEPTA recently renewed advertising contracts with Titan, which would have to negotiate with TIS over the ads on the glass doors. Assistant General Manager Francis Kelly said SEPTA is considering platform screen doors, but admitted to Metro that talks with TIS “didn’t even get that far.”